Power transmission



Aug- 24, 1965 c. R. HlLPER-r 3,202,018

POWER TRANSMISSION Filed April 16, 1962 10 Sheets-Sheet l Aug. 24, 1965c. R. HlLPr-:RT

POWER TRANSMISSION 10 Sheets-Sheet 2 Filed April 16, 1962 elw Aug. 24,1965 c. R. HILPERT POWER TRANSMISSION 10 Sheets-Sheet 5 Filed April 16,1962 Aug. Z4, 1965 c. R. HILPERT POWER TRANSMISSION l0 Sheets-Sheet 4Filed April 16, 1962 mwN www.

Aug 24, 1965 c. R. HILPERT 3,202,018

POWER TRANSMISSION Filed April 16, 1962 10 Sheets-Sheet 5 W Q N N @x NITU/afan N QQ Conrad/E/lpef Aug- 24, 1965 c. R. HILPERT 3,202,018

POWER TRANSMISSION Filed April 16, 1962 lO Sheets-Sheet 6 lili/ fon @vwdW12/per Aug. 24, 1965 c. R. HILPl-:RT

POWER TRANSMISSION l0 Sheets-Sheet '7 Filed April 16, 1962 Aug. 24, 1965C. R. HILPERT POWER TRANSMISSION 10 Sheets-Sheet 8 Bmw.

Filed April 16, 1962 IN1/Inform Cdfrc//Fffilpew Aug. 24, 1965 c. R.HILPERT POWER TRANSMISSION 10 Sheets-Sheet 9 Filed April 16, 1962 www,

Aug. 24, 1965 c. R. HILPERT POWER TRANSMISSION l0 Sheets-Sheet lO FiledApril 16, 1962 United States Patent O FnZtBZiS i lltWidi- 'ERANSMESSEUNConrad R. Hiipert, Winnebago, liii., assigner to Twin Disc ClutchCompany, Racine, Wis., a corporation of Wisconsin e Filed Apr. lo,19162, Ser. No. 187,741 l2 illairns. tCi. '7d- 732) My invention relatesgenerally to power transmissions including `in order of power dow aconstant speed power source, a friction clutch conditioned for slippagecontrol to vary torque or speed output therefrom, and a bladed memberrotating in a huid.

In its broadest aspect, the invention comprehends the ,interposition ofa variable capacity clutch between a `constant, speed power source and arotating bladed member operating in a fluid wherein the member absorbstorque proportional to some function of its speed and the clutch servesas a torque and speed control for the member. Examples ot such bladedmembers are ccntrifugal pumps, air fans, air and water propellers,hydraulic couplings and hydraulic torque converters. For convenience indescription, most of the applications of the invention disclosed hereinutilize hydraulic torque converters whose impellers constitute the abovenoted bladed member and one application is concerned with a centrifugalpump.

It is recognized that positioning a friction plate clutch ahead of aconverter or of any bladed `member in a power train is generally old,but such located clutches, so far as known, have been utilized toultimately provide `the usual solid connection betwc-en the inputandoutput thereof. Any slippage that occurred was merely for the purpose.of softening or modulating the full engagement of the clutch and hencewas incidental to the overall operation. Torque and speed control wereotherwise determined.

In the present instance, slippage of the clutch is a `char cteristic ofthe operation` and Vis a means of control for adjusting the power,torque or speed from aV constant speed power source to a load withoutthe generation of extreme losses.

While a slipping clutch develops heat, it has been ascertained that,considering the overall transmission, the maximum clutch heat horsepowernever exceeds about 15% of the maximum input horsepower to theconverter, or bladed member generally. This maximum clutch heathorsepower occurs when the clutch is slipping approximately 33.U% of themaximum power source speed and this clutch heat is approximately l5% ofthe total power source horsepower when a converter, for example, isoperating at approximately two-thirds of the speed of the power source.By providing an adequate heat exchanger to cool the converter at thistwo-thirds speed point, the slipping clutch will not cause overheatingand,

`in fact, slipping of the clutch will cause a reduction in the totalheat load on the cooling system.

The improved transmission is useful with any type `of power source andparticularly with those types which cannot be directly coupled to a loadwithout the addi- `tion of some device, manually or automaticallyoperated, `for controlling the torque or speed transmitted to the load.Examples of such power sourcesare induction `motors, gas turbines andturbo-charged diesel engines.

The transmission provides for innitely smooth or stepless control and isinstantly responsive to the demands of the operator from zero outputspeed or torque to full speed or torque. it is therefore possible toinch the load as desired and to operate the load at any desired reducedspeed for sustained periods without excessive heating.

A special application of the improved transmission hzi Patented Aug.24.-, 1965 ICC e is in the field of electrically operated vehicles, suchas locomotives, railway cars and buses. The power usually available forthe operation of such vehicles` in the United States is provided by athree-phase currenthaving the stan-dard frequency of 60 cycles persecond although in some localities specialized circuits having afrequency of 25 cycles havebeen employed in electric railway operationsince such frequency enabled to use of commutator motors which arecharacterized by high starting torque and economic speed control.

For the most part,`however, electric railway operation utilizes thestandard 60 cycle frequency current but not directly. While the ordinaryinduction motor can be driven directly byiathree-phase current ofnorm-al frequency and voltage and is cheaper than the commutator motor,the poor starting `characteristics of the former motor and thecomplications required to control its speed rule it out for electricrailway operation. Recourse `is had to one of the available `forms ofconversion sourceV anon-variable speed, alternating current motor,-

such as a squirrel cage induction motor. All control is exercised byslipping a master clutch in conjunction with a torque converter andauxiliary clutches for determining foward and reverse drives and forbraking.

There has been proposed for electric railway opera- ,tion7 see U.S.Letters Patent No. 2,839,011, dated lune 17,` 1958, a transmissionincluding an induction motor and an hydraulic torque converter, butcontrol in this instance is achieved by varying the flow of the workingliquid in the converter through selective positionings of `one or moreof the blade sets, impeller, turbine or stator. Variable bladesettingsalect the eiiiciency of the couverter. The present transmission does notrequire a converter of a` particular design since the control isexercised elsewhere.`

it is therefore the principal object of the invention to provide a powertransmission including in series power flow relation a constant speedpower source, .a controliable slip, friction plate clutch, and a bladedmember rotatable in a` fluid.

A further object is to provide a power transmission i of the above typewherein the bladed member is constituted by the impeller of an hydraulictorque converter of the rotating or stationary housing type.

A further object is to providea transmission of the character indicatedin which the clutch is of the hydraulically actuated type and may bepositioned externally Aof or within the converter, and the actuatingpressure therefor is either manually controlled or :automaticallyetermined in relation to the outspeed or torque of the converter. i

A further object is to devise a transmission as above which incorporatesa controllable'brake between the out-` put of the clutch and the inputofthe converter, the engagement of the brake preventing creepingrotation of `the converter impeller occasioned by shear of the coolingning at its normal, constant speed and the vehicle descending a hill,either a constant speed of the vehicle can be maintained or the vehiclebrought to a stop by effecting a braking action occasioned by asimultaneous reverse rotation of thev turbine and a controlled forwardand normal rotation of the impeller determined, respectively, by anoperation of the reverse gearing and a selected contact of the plates ofthe master friction clutch.

A further object is to effect dynamic braking in a vehicle transmissionof the character indicated by employing a bladed, coupling type retarderassociated with the converter output shaft and to which pressure liquidis diverted from the supply line to the converter.

In the drawings:l

FIG. 1 is a sectional elevation schematically showing a power trainincluding a constant speed power source, a stationary housing, hydraulictorque converter, and an hydraulically actuated, friction plate clutchinterposed therebetween and controllable as to slip for regulating powerinput to the converter.

FIG. 2 isa fragmentary, sectional schematic of a rotating housing,hydraulic torque converter which may be utilized in the power trainshown in FIG. 1 as a substitute for the stationary housing converter.

FIG. 3 is a fragmentary, sectional schematic of a stationary housingconverter which may be used in the FIG. 1 power train, the distinctionfrom the latter being that one oil source provides working oil for thetoroidal circuit of the converter and oil pressure for the master clutchunder the control of a regulating valve.

FIG. 4 is a fragmentary, sectional schematic of a stationary housingconverter which may also be used in the FIG. 1 power train and in whichslippage control of the clutch is automatically regulated by Pitot tubesin the Ytoroidal circuit of the converter which may be adjusted to senseeither output speed or torque of the converter.

FIG. 5 is a fragmentary, sectional schematic of a power train which isidentical with FIG. 1 except for the interposition of a brake betweenthe clutch and converter to provide a combination braking and poweringof the impeller to improve the overall control.

i FIGS. 6 and 7 are sectional schematics of a modified power trainwherein the slip control clutches are incorporated within the bodies ofthe converters, the latter respectively being of the stationary androtating housing types.

FIG. 8 is a fragmentary, sectional schematic showing .a variant of theconverter shown in the FIG. 6 power train wherein the clutch ishydraulically released.

FIG. 9 is a fragmentary, sectional schematic of a converter which variesfrom those shown in FIGS. 6, 7 and 8 by the inclusion of braking means.

FIGS. 10- to 14, inclusive, are sectional schematics showjing variantforms of power trains embodying the invention which are moreparticularly intended for use with a constant speedyelectric powersource, such as an induction ,motor, that is powered by an alternatingcurrent having Athe standard 60 cycle frequency and is particularlyadapted for electric vehicle op-eration7 such as commuter trains.

FIG. is a schematic view similar to FIG. 1 wherein the output connectionof the clutch is to a centrifugal pump generally indicative of arotatable bladed member loperating in' a fluid.

Referring to FIG. l, the numeral 1@ designates a conventional, constantspeed power source of the type which ycannot normally be connected to aload without auxiliaries kof some kind for controlling the torque orspeed transmitted to the load. General examples of such power ysourcesare induction motors, gas turbines and internal combustion engines. Thepower source 10 is drivably connected through a shaft 11 with an annularshell l2 that has driving and rleative sliding connection with a'plurality of annular, friction clutch plates I3 which are rilternatelyrelated to a similar group of clutch plates 14 that are drivablyconnected and slidable relative to a i shaft i5. Collectively, theplates 13 and 14 define a friction clutch 16 which is hydraulicallyactuated by a suitable oil as presently desccribed and which whenengaged to any extent are limited in their axial movement by an abutmentplate 17 carried by the shaft 15.

Axially spaced from the clutch 16 is an annular reaction plate 18carried by the'shaft I5 and held against axial movement and slidable onthe periphery of the plate 18 is a cylindrical shell t9 havingtransverse end walls 20 and 21 which in conjunction with the shaft 1.5and reaction plate 13 respectively define annular' engaging and balancechambers 22 and 23, the chamber Z2 being appropriately sealed relativeto the shaft 15 and reaction plate 18. Cooling oil is constantlysupplied to the plates of the clutch 16 by a suitable pump 24 whoseoutput connects through a pipe 25 with one end of a longitudinal passage26 in the shaft i5 and the opposite end of this passage communicatesthrough a plurality of transverse passages 27 with the inner portions ofthe plates of the clutch 16 for outward radial ow thereover and deliveryto a suitable sump (not shown). The passage 26 also connects through atransverse passage 23 with the balance chamber 23 from which the oilconstantly discharges to the sump through `an annular orifice 29. Thechamber 23 is maintained full during its volume changes and serves tobalance the centrifugal pressure on the oil in the engaging chamber 22.

The shaft 15 is drivably connected to an impeller 3) forming part of anhydraulic torque converter 31 which otherwise includes a turbine 32connected to a load shaft 33 and a stator 34 carried by the stationaryhousing 35 of the converter, the impeller, turbine and statorV beingrelated to form the usual toroidal circuit. The single stage converterSi, as shown, is merely by way of example since the invention is notdependent upon a particular converter design and all converters exhibitsimilar input characteristics. Actually, the broadest aspect of theinvention is concerned with the utilization of a slippable frictionclutch as a means of regulating the power input to a bladed memberoperating in a uid medium where such power is derived from a constantspeed power source. A constant oil flow at a basic, static pressure ismaintained through the converter 31 in accordance with conventionalpractice by means of an appropriately driven pump 36 whose outputconnects by a pipe 37 with the interior of the converter 31 and such owmay be discharged through a pipe 38 to a conventional heat exchanger(not shown).

To control the clutch 16 in any slipping or a fully engaged position, apump SS- delivers oil from a suitable source through a pipe it? to achamber il forming part of a regulating valve 42 in which isreciprocable a piston 43. Movement of the piston 43 towards the right iseffected by a pivoted hand lever 44 acting through a yieldable meanssuch as a helical spring 45 which abuts the piston 43. The chamber 41connects successively through a pipe it? and a longitudinalL passage i7in the shaft 15 with the engaging chamber 22.

In the position of parts shown in FIG. 1, the piston t3 occupies itsfully retracted position in which it uncovers a passage 48 connectingwith the chamber 41 and a sump 49 so that the full output of the pump 39is delivered to the sump 49 and the clutch 16 stands released. It willbe apparent that as the piston 43 is moved towards the right, pressurein the pipe 46, passage 47 and engaging chamber 22 begins rising and theend wall 26 starts moving in a direction to engage the clutch 16. Afterthe clearance between the clutch plates 13 and 14 and the abutment plate17 has been taken up and the friction surfaces are in Contact, torquetransmission by the clutch 1.6 is entirely controlled by the position ofthe piston 43, such control being infinitely variable.

A rotating housing, iydraulic torque converter 48 may be used instead ofthe stationary housing converter 31 in the FIG. 1 power train, thelatter structure being otherwise unchanged. Referring to FlG. 2, thenumeral 49 designates the input shaft of the converter i8 andcorresponds to the shaft in FiG. 1 in that it connects through theclutch 1d with the power source 1t). The shaft 49 carries an impellerS@` which is torodial circuit related in the conventional manner to aturbine 51 carried by the rotating housing 52 and a stator 53 which isheld against rotation during periods of torque multiplication by anoverrunning clutch 54 conventionally related to a fixed part 55 of theadjacent equipment. Working oil at a basic, static pressure iscontinuously supplied by a pump 56 under conventional regulation througha passage 57 in the converter output shaft 53 to the interior of theconverter and is discharged therefrom through a passage 59 in the shaft49 and a pipe oil to a sump (not shown). Except for the capacity of thestator S3 to freewheel when the turbine 51 attains a determined speed,the operation of the power train incorporating the converter whencoupled to the power source 1d through the clutch 15 is identical withthe FIG. 1 train.

ln FlG. 3 is shown a further modiication of the FIG. 1 train which onlydiiers therefrom in the use of a single oil supply for the converter andclutch and because of this similarity, parts in FIG. 3 which arefunctionally identical with those in FIG. l are designated by the samenumerals. The single oil supply is continuously furnished by a pump 61whose output connects through a pipe 62 with the interior of theconverter 31 to constantly maintain a basic static pressure in thetoroidal circuit thereof and the discharge from the converter 31 flowsthrough a pipe 63 to the chamber 41 of the regulating valve 42. As inFIG. 1, the chamber 41 successively connects through the pipe 4d andpassage i7 with the clutch engaging chamber 22. i

ln the fully retracted position of the pistonV 43, it fully uncovers theinlet end of a pipe 64 whose opposite end connects with the passage Z5and hence with the balance chamber 23 and the inner edges of the clutchplates `13 and 14 so that the clutch 16 stands released. Since oil owingthrough the pipe d4 ultimately reaches the sump, it will be apparentthat, to this extent, the pipe 64 is functionally similar to the pipe 4din FiG. l. As the piston 43 is moved towards the right, pressure in thepipe Se and in the toroidal circuit of the converter 31 begins risingand thesame variable, torque transmitting condition of the clutch 16 isobtained.

Referring to FIG. 4, there is shown a modilied power train whichutilizes the same converter and the same type of clutch as in FlG. 1,but differs from the latter train in that the clutch is fully engaged atthe beginning of operation and sensing means positioned in the toroidalcircuit of the converter is responsive to converter output torque oroutput speed, which ever is chosen, to reduce the engaging pressure onthe clutch and hence its torque transmitting capacity. i

The constant speed power source 10 is drivably connected to anhydraulically actuated, friction plate clutch d5 which may be identicalwith the clutch 15 except that the formel-s driving and driven platesdei and 67, respectively, are fully engagedas shown at the instant ofstart. The clutch structure also includes engaging and balance chambers63 and t191 which are positioned on opposite sides of an axially fixedreaction member 7d carried by a clutch output shaft 71 and otherwiseincluded within a cylindrical shell 72 having end walls 73 and 74,V allrespectively.

Oil supply `lor the balance chamber 69 and cooling oil for the clutchplates 66 and 67 is continuously provided by apump '7S underconventional regulation whose output connects by a pipe 7d with one endof a longitudinal passage 7'7 in the shaft 71. The oppositeend of thepassage 77 connects by transverse passages 78 with the inner portions othe clutch plates 616 and 67 from which the oil il-ows to a sump (notshown) and an intermediate part of the passage 77 connects through atransverse passage '79 with, the balance chamber at) from which the oilcontinuously bleeds to the sump through an annular orifice titl in theend wall 74.

The shaft 71 has power input connection to the impeller till of astationary housing, hydraulic torque converter 82 and the impeller S1 istoroidal circuit related in the conventional manner to a turbine havinga load shaft 84 and a stator $5 carried by the converter housing 816.Working oil at a basic, static pressure is continuously supplied to theinterior of the converter 82 by a pump 87 through a pipe 553 and isdischarged through a pipe S9 to a heat exchanger (not shown).

The FIG. 4 power train is characterized by an automatic control on theengaging pressure of the clutch 65 that is responsive to a selectedfactor, either converter output torque or output speed, and when suchcontrol point is reached, the engaging pressure is reduced to provide aslipping condition of the clutch 65.

A pump @u having conventional relief control (not shown) continuouslysupplies oil under pressure through a pipe 91 to a chamber 92 formingpart `of a regulating valve 93 and the chamber 92 connects through apipe 94 and a passage 95 in the shaft 71 with the engaging chamber 63.Reciprocable within the valve g3 is a piston 96 which is connected by arod 97 with a piston 98that is reciprocable within a` housing 99 anddehnes therewith chambers tu@ and 101 for a purpose presently explained.A spring 162 biases the piston 9S and hence the piston 96 in a directionclosing a passage 103 Which under certain conditions connects thechamber 92 with a sump 104; With the piston 9d positioned as shown, alloutput of the pump Sit is directed to the engaging chamber 63 so thatthe clutch d5 is fully engaged which is the condition at the start ot'operation. v

Automatic control on the magnitude of the clutch engaging pressure isprovided by Pitot tubes 1% and 1tl6 which extend into the toroidalcircuit 107 adjacent the inlet and outlet of the blades of the stator85. Externally of the converter SZ, the litot tubes lili and 1% con`nect by pipes 16S and M59 with the chambers lili) and lull, allrespectively. Y

The Pitot tubes 11.?5` and little are responsive to ilow conditions inthe toroidal circuit 107 and may be conditioned to sense a determinedconverter output torque or output speed. Theinlet openings of the tubes105 and 1% are angled relative to the direction of toroidal ow so as toexhibit a differential pressure that is proportional to either of theabove factors, the pressure transmitted by the tube 1&5 being alwayshigher than that by the tube lila. For sensing output torque, the tubes165 `and 166 are adjusted to respond to the flow condition at or nearstall, and for sensing output speed, the tubes are adjusted to respondat or near racing. Whichever sensing control is chosen, the totalpressures transmitted to the chambers tu@ and lill will be a summationof the static liquid pressure in the toroidal circuit 107 and that dueto liquid iiow past the tubes and 106 but the static pressure, as tar ascontrol is concerned, will be essentially eliminated due to thesubstantially equal areas on opposite sides of the piston 93. Hence,when the control point is reached, pressure in the chamber 10) exceedsthat in the chamber 191 plus the thrust `of the spring 192 and thepiston 96 is moved to uncover the inlet to the passage 163. Accordingly,the engaging pressure in the chamber 68 is reduced and the clutch 65begins to slip and reduce the converter output speed or torque, aschosen, to the desired amount.

In FIG. 5 is shown a further modification of the FlG. 1 power trainwhich differs therefrom only in the interposition oi a brake between theclutch 16 and the converter Ell. Parts in FIG. 5 which` are `identicalwith those i in FIG. l are designated by the same numerals.

The numeral 11i) indicates a iixed, annular member which encircles andis coaxial with the shaft 15 between the clutch 1b and the converter 31.Projecting inwardly from the member 110 is an annular flange 111cm whoseinner periphery is axially slidable a cylindrical shell 112 having onopposite sides of the lange 111 end Walls 113 and 114 which are slidablealong the inner surface of the member 11@ and denne annular chambers 115and 116, respectively. lt will be understood that suitable sealing rings(not shown) would be employed where required. Within the member 111B, abrake disk 117 has splincd connection to the shaft 15 and a plurality ofsprings 118 equispaced around the shell 112 and interposed between thelange 111 and end wall 1111 bias the latter into friction brakingengagement with the disk 117 and this disk into like engagement with anannular, abutment flange 119 extending inward of the member 111B. A vent121i connects the chamber 116 with the atmosphere to insure free actionof the springs 113.

Connecting with the pipe i6 which conducts pressure to the passage 47and thence to the engaging chamber 22 of the clutch 16 is a pipe 121whose outlet connects with the chamber 115 and a pipe 122 leading fromthe pipe 25 has its delivery end directed to continuously supply coolingoil to the brake, generally designated by the numeral 123, and such oilreturns to the snmp in the annular location 12d. With the piston in theposition shown in FlG. 5, the output of the, pump 39 is delivered to thesump d@ so that the clutch 16 stands released. The brake 123, however,is engaged due to the thrust of the springs 11S and this braking actionprevents any possible torque application to the impeller 3l) due to thecooling oil drag on the plates of the clutch 16 when released whichmight create an unwanted torque on theV converter output shaft 33.lll/hen the .piston i3 is moved to the right, the rise in pressure inpipe 46 not only moves the clutch plates 13 and 14 into contact toestablish any desired torque transmission as explained for FlG. 1, butalso establishes pressure in the chamber 115 to release the brake 123 toany desired extent. This modification therefore provides an improvementin control by reason of the combined braking and powering of theimpeller 3d.

In the power trains described above, the controllable clutch is locatedexternally of the converter, but in FG. 6 is shown a power train havingthe indicated characteristics wherein the clutch is positioned withinthe converter. Referring to FlG. 6, the numeral 12S designates theconstant speed power source which connects by a shaft 126 with a hub 127positioned within the stationary housing 128 of an hydraulic torqueconverter 12.9. The hub 127 has driving and relative sliding connectionwith a plurality of friction clutch plates 131D which are alternatelyrelated to like plates 131 to provide a friction clutch 132, the plates131 having driving and relatively slidable connection to a cylindricalshell 133 that is coaxial With the clutch 132 and projects from animpeller 134. The impeller 134 forms part of a conventional toroidalcircuit 13S that otherwise includes a turbine 13e connected to a loadshaft 137 and a stator 133 carried by the housing 128.

Sealably slidably within the shell 133 is a piston 139 from which on theside facing the clutch 132 projects an annular pressure ring 14@ thatregisters with and engages the clutch 132 when the piston 139 ishydraulically actuated'as presently described. The piston 139 is biasedto 8 144 and 146 constantly communicating through a passage 1417provided in the plate 143.

For control of the FIG. 6 power train and cooling of the clutch 132, thefollowing instrumentalities are provided. A pump constantly supplies oilto the toroidal circuit through a pipe 1li@ and discharge from thiscircuit is through a pipe 15? to a chamber 15 forming part of aregulating Valve 153. Reciprocaole within the valve 152, is a piston 153which is shiftable by a pivoted handle 15a acting through a yieldablemeans such as a helical spring 155.

To cool the plates of the clutch 132, the toroidal circuit 135 is tappedby a plurality of orifice passages 156 which direct a part of theworking oil to the outer portions of the clutch plates 13? and 131 fromwhich it :flows inwardly to a chamber 157 included between the hub 127and piston 139. The chamber 137 connects through a passage 153 in theshaft 12d with a pipe 159 leading to a sump.

With the piston 133 in the position shown in FIG. 6, it uncovers a pipe161 leading to a sump 1f?. so that all output of the pump 148 isdelivered thereto and the piston 139 is retracted to the clutch releaseposition shown by the springs 141. As the piston 153 is moved to theleft, pressures begins rising in the toroidal circuit 135 and also inthe chamber which connects with the circuit 135 by a suitable spacing ofthe shell 133 and member 145 that creates an annular passage 153. Sincethe chambers 145 and 14K?- communicate through the passage 147, pressurebuild-up in the latter chamber moves the piston 139 in clutch engagingdirection. Regulating movement of the piston 153 therefore not onlyprovides for inlinite variations in control of the clutch 132 withrespect to its torque transmitting condition, but also varies the basicpressure in the toroidal circuit 135. Suitable seals are provided whererequired to maintain separate the clutch oil cooling liow and the oilwhich applies pressureto the piston 139.

ln FlG. 7 is shown a variation of the PEG. 6 power train, the differenceconsisting primarily in the use of a rotating housing, hydraulic torqueconverter. The numeral 164- designates the constant speed powerV sourcewhich connects by a shaft 165' with a hub 16e positioned within arotating housing 167 of an hydraulic torque converter 168, the housing167 being connected in the usual manner with a load shaft 169. As inFlG. 6, the hub 166 is connectible through a friction plate clutch 17)with an anuular shell 171 which is coaxial with the shalt 16S andprojects from an impeller 172 that is related in the usual manner to aturbine 173 carried by the housing 167 and a stator 17d which, duringperiods of torque multiplication, is held against rotation by anoverrunning clutch 175 conventionally related to the stator 17d and afixed part 176 of adjacent equipment. ri`he impeller 172, turbine 173and stator 174 denne a toroidal circuit 177.

Also in FIG. 7, the end of the shell 171 remote from the impeller 172 isclosed by a plate 173 and reciprocable within the shell 171 between theclutch 17@ and plate 178 is a piston 173 that is identical with thepiston 139 in FIG. 6. The plate 173 defines with the housing 167 andpiston 179 chambers 13@ and 181, respectively, which communicate througha passage 132 in the plate 173 and the piston 179 defines with the hub166 a chamber 153. The piston 179 is biased in the clutch releaseposition by a plurality of springs 1311 having their ends respectivelyabutting the piston 179 and plate 173.

Oil for actuation of the clutch 17@ and toroidal circuit 177 is suppliedby a pump 185' whose output is delivered successively through a pipe1li-i1, collector ring 137, and passage 3S in the housing 167 and loadshaft 133 to the chamber 13@ and thence through the passage 132 to thechamber 181. Cil in the chamber 1S@ also ov s through an annular passage113@ between the housing 167 and shell 171 to the toroidal circuit 177and from the latter, the oil lows successively through a chambercentrally of the converter 16S, a passage 191 in the shaft 165, acollector ring 192 and a pipe 193 to a chamber 194 forming partof aregulating valve 195. A piston 196 is shiftable in the valve 195 underthe contorl of a handle 197 acting through a helical spring 198.

For cooling of the plates of the clutch 170, the toroidal circuit 177 istapped by a plurality of orifice passages 199 which direct the oil tothe outer part of the clutch 170 and such oil passes successivelythrough the chamber 183, a passage 200 in the shaft 165, and a collectorring 201 tothe sump 202. `As in FIG. 6, with a piston 196 in the fullyretracted position shown, it uncovers a pipe 203 leading to a sump 204so that the oil supplied by the pump 135 ultimately reaches the sumps202 and 204 which may be combined in a single sump. The operation of theFIG. 7 modificationis identical with that of FIG. 6 with respect tocontrolling the converter static pressure and any desired torquetransmitting condition of the clutch 170. It will be understood thatsuitable seals would be employed where necessary to maintain theintegrity of the cooling flow to the clutch 170 and `that to thetoroidal circuit 177 and the engaging chamber 181.

In FIG. 8 is shown a variant mode of releasing a clutch positionedinteriorly of a converter and while shown in connection with astationary housing converter such as in FlG. 6, it is also `applicableto the the rotating type shown in FIG. 7. Since the pump for supplyingthe toroidal circuit and the clutch engaging pressure and the internalconstruction of the converter except for the clutch engaging piston areidentical with the similar parts in FIG. 6, like parts are designated bythe same numerals.

In FIG. 8, the clutch 132 is released as determined by the fullyretracted position of the piston 153 which rei moves clutch engaingpressure applied to one end of a piston 205 that may be shapedlike thepiston` 139 in FIG. 6 except for the spring pockets 142 which areomitted. Movement of the piston 205 to the release position ishydraulically eiected as will now be described.

A pump 206 equipped with conventional relief means (not shown) deliversoil through a pipe 207 to one end of a casing 208 forming part of acontrol valve 209 and, in the position of parts shown, specically to theinterior of the casing 208 between spaced lands 210-210 of a spool valve211 whose stem extends externally of the casing 208 for convenientreciprocation. In this position Vof the spool valve 211, the pipe 207connects through a pipe 212 and a collector ring 213 with the passage158 in the shaft 126 leading to the chamber 157 to thereby provide re`lease pressure for the piston 205. It is recognized that this pressurewould likely abut the piston 205 against the plate 143, or against someother yconvenient stop (not shown), but for purpose of illustration thepiston 205 is shown spaced from the plate 143 to clearly show thechamber 144 for receiving the clutch engaging pressure.

When it is desired to engage the clutch 132 to any desired extent byappropriate shifting of the piston 153 as described for FIG. 6, theclutch release pressure is shut noi by shifting the spool valve 211 tothe left to mask the delivery end of the pipe 207 and to connect throughthe control valve 209 the pipe 212 with a pipe 214 leading to a sump215.

Referring to FIG. 9, there is shown a Variation of the FIGS. 6 and 7power trains in which a braking restraint is imposed on the powering ofthe impeller for the same general purpose as described for the FIG. 5train.

The numeral 216 designates a constant speed power source which connectsthrough a shaft 217 with a disk 218 which carries an annular shell 219which extends towards the power source 216 and is coaxial with the shaft217. A friction plate clutch 220 whose plates are alternately connectedto the shell 219 and to an extension 221 carried by an impeller 222provides when engaged the driving connection between the shaft 217 andimpeller 222. The impeller 222 forms part of a stationary housing,hydraulic torque `converter 223 and is related 232 interposed betweenthe piston 230 and the impeller hub 233. The springs 232 aresubstantially included in an annular housing 234 extending laterallyfrom the piston 230 and whose inner and outer, annular walls 235 and 236are slidable on the shaft 217 and extension 221, all respectively. Thehousing 234 is vented to the atmosphere through a passage 237 in theshaft 217 to insure free action of the springs 232.

An annular, brake plate 238 carried by and axially slidable relative tothe converter housing 228 is interposed between the impeller hub 233 andan annular piston 239 which is slidable inan annular pocket 240 providedin the 'converter housing 228 and helical springs 241 respectively:abutting the housing 228 within the pocket 240 and an end wall of anannular recess 242 provided in the piston 239 bias the latter to theimpeller braking position shown in FIG. 9.` The pocket 240 is Vented tothe atmosphere by a passage 243 to maintain free action of the springs241.

Oil supply is provided by a pump 244 whose output flows through a pipe245 to the toroidal circuit 229 and from the latter to an annularpassage 246 which connects with a chamber 247 included between the disk218 and a cup-shaped member 225, the chamber 247 communieating with theclutch engaging chamber 231 through a passage 248 in the disk 218. The`passage 246 also con-` nects through passages 249 and 250 in thecup-shaped member 225 and converter housing 228, respectively, with apipe 251 leading to `a chamber 252 forming part of a regulating valve253.

Slidable in the regulating valve 253 is a piston 254 which is actuatedby a handle 255 operati-ng through a helical spring 256. In the fullyretracted position of the piston 254, it fully uncovers a pipe 257 whichconnects with a sump 25S. Accordingly, in the shown position of thepiston 254, the output of the pump 244 flowsto the sump 258, the clutch220 is released by the springs 232, and the brake 259, comprising theimpeller hub 233, brake plate 238 and piston 239, is engaged by thesprings 241. Therefore, the impeller 222 is held stationary againstotherwise possible rotation and unwanted torque on the load shaft 226which might be set up by oil drag on the plates of the clutch 220.

When the piston 254 is moved towards the right, the pressure begins torise in the toroidal circuit 229 which begins to release the brake 259and also in the chamber 231 so that the piston 230 begins moving in thedirection to engage the clutch `220. In some positions of the piston254, the impeller 222 may be subjected to a combined braking andpowering action` to vary torque on the load shaft 226 and with the brake259 fully released, n

torque on the load shaft 226 is a function of the variable, controlled`pressure acting on the piston 213.

In FIGS. l0 to 14, inclusive, are shown a variety of power trains whichemploy a constant speed power source and a master, controllable slip,friction clutch as a means for varying the torque and speed of a loadshaft and which are particularly designed for electric railwayoperation. As noted` above, it is possible with this type of power trainto employ an induction motor as thelconstant speed power sourceoperating with standard single or threephase, alternating current havinga frequency of 60 cycles. Electric power systems of this character arereadily available and the improved power train makes it possible toutilize such systems directly, thus elimi- 'shoppie nating thecomplexities involved in the use of direct current motors which is thecommon practice.

Referring to FIG. 10, the numeral 260 designates an induction motorwhich runs at constant speed and is -drivably connected to an annulus261 that in turn is controllably connected to a converter input shaft 22by means of a master, friction plate clutch 263 which is hydraulicallyactuated as presently described and whose plates are conventionallyrelated to the annulus 2F52 and input shaft 262, respectively, andgripped against an abutment ring 264 provided on the shaft 262.

An annular reaction plate 265, held against axial movement, is carriedby the input shaft 262 and on its periphery is slidable a cylindricalshell 2456 having annular end walls 27 and 26S which define with theshaft 262 and Yreaction plate 265 annular, clutch engaging and balancechambers 2h91 and 271B, respectively.

The input shaft 262 connects with the rotating housing 271 of anhydraulic torque converter 272 which is shown nas being of the singlestage type, but this is not a limiting factor. Further, it is possibleto employ a stationary housing converter since the essential ingredientof the `invention is the control on the impel'ler. The housing 2'7i'carries an impeller 273 which is conventionally related -to a turbine274 drivably connected to an intermediate shaft275 and to a stator 276which is held against rotation during periods of torque multiplicationby the usual overrunning clutch 277 interposed between the stator hub27S and a fixed part 279 of the adjacent equipment. 'The impeller 273,turbine 274 and stator 276 define the usual toroidal circuit 28).

The output end of the intermediate shaft 275 connects through a clutchcontrolled, forward and reverse mechanism, genera-lly indicated by thenumeral 281, with a load shaft 282. Specifically, the mechanism 231 in-`cl-udes an annular reaction member 283 carried by the intermediateshaft 275' and held against axial movement and slidable on the peripheryof the reaction member 283 is a cylindrical shell 234 having annular endwalls 285 and 226 kwhich define with the react-ion member 283 and theintermediate shaft 275 annular, clutch engaging chambers 287 and 288,all respectively.

The intermediate shaft 275 is connectible through a friction plateclutch 289 with a coaxial, annular ange 29@ carried by a bevel gear 291attached to the load -shaft 232, the clutch 289 being engaged when theshell 2M is moved to the right to grip the plates of the clutch .289against an abutment ring 292 carried by the shaft 275 to thereby provideforward drive. For reverse drive, the intermediate shaft 275 isconnectible through a friction plate clutch 293 with an annular flange294 carried by a suitably journaled bevel gear 295, the flange 294iandgear 295 being coaxial with the intermediate shaft 275 and the gear 295meshing -with an idler bevel Agear 2% which in turn meshes with the gear291, the gear 2% .being held against revolution about the inter--mediate shaft 275. The clutch 2% is engaged by movement of the shell234 to the left which grips the plates 'of the latter clutch against anabutment ring 297 carried by the intermediate shaft 275.

The clutches 263, 289 and 293 and the converter 272 are included in anhydraulic circuit whose arrangement and control will now be described. Apump 293 with- Vdraws the `oi-l from a sump 299 for delivery serially Ythrough a heat exchanger 3th) and `filter Still to the inlet of aconventional spring loaded, relief valve 322 which connects with andunder operating conditions constantly maintains in a 4pipe 363 leadingto the clutch chambers v237 and 23d a relatively high pressure of, forexample,

l5() to 20() p.s.i. v v

The oil relieved by the valve 362 flows successively through a pipe 394,a collector ring 3=i35 and a passage Y3% included between the housing27d and the hub of the stator 275 to the toroidal circuit between thestator '27d and impeller 273, and the outlet from the toroidal lcircuit23d is successively from between the turbine 274 and stator 276, apassage 337 collectively defined Iby the hubs of the turbine 274 andstator 276 and the shaft 275 to a collector ring 3&8 which connects witha pipe 399 leading to a chamber 3l@ provided in a regulating valve 311i.

As in the other modifications, the regulating valve 311 includes apiston 312 which is manually operable through a spring 323 and oilpressure in the chamber 31u, which under operating conditions isestablished by the position of the piston 312 in relation to a reliefoutlet 3M connecting with one end of a pipe Sid, is transmittedsuccessively through a pipe 3io, a collector ring 317 and a passage 518in the input shaft 262 with the master clutch engaging chamber 269. Thepipe 3io is tapped by a pipe El@ including a throttling orifice 32%)which connects through a collector ring 321 with a passage 322 in theinput shaft 262 leading to the balance chamber 270. Oil is continuouslysupplied to the balance chamber 27d and discharge therefrom is throughan annular orifice 323 'to the sump 229. The other end of the reliefpipe 315 connects successively through a collector ring 324i and apassage 325 in the input shaft 262 with the inner portions of the platesof the master clutch 263 to continuously supply a cooling oil tiowthereto which thereafter collects in the sump 299.

rEhe delivery end of the high pressure .pipe 323 conects with an inletport 326 of a selector valve 327 which also includes outlet ports 323and 329, and ports 33t? and 33t which connect with the sump 299.Reciprocable within the casing 332 of the selector valve 327 is a valvestem 333, conventionally shown as spool type, having end lands 334 and335 and spaced therefrom an intermediate land 336. In this connection,it will be understood that wherever valve stems are denoted as being vofthe spool type, this is by way of example only and not restrictive. Theoutlet port 32S connects successively through a pipe 337, a collectorring 3:33 and a passa-ge 39 in the intermediate shaft 275' with thereverse, clutch engaging chamber 2&5, and the outlet port 329 connectssuccessively through a pipelit, a collector ringil and a passage 342 inthe intermediate shaft 275 with the forward, clutch engaging chamber2&7. The high pressure pipe 323 is tapped between the relief andselector valve 302 and 327, respectively, by a pipe 343 which includes athrottling orifice 344 and connects successively through a collectorring 345 and a branched passage 346 in the intermediate shaft 275 withthe inner portions lof the plates of the clutches 239 and 293 tocontinuously supply cooling oil iow thereto which finally discharges tothe sump 299.

in the position of parts shown in FG. l0, .it is considered that themotor 26) is running at the desired constarrt speed, that the regulatingvalve piston 322 is fully retracted to the right so that engagingpressure is not present in the master clutch chamber 269 and the clutch263 isV fully released, and that the relief valve 322 is open as shownto establish the high pressure in the pipe 3&5. in the shown position ofthe selector valve 327, the intermediate land 335 masks the inlet port326 and the end lands 323 and 334 provide for communication between theoutlet `and sump connecting ports 32S and 339, and between the outletand sump connecting ports 329 and 33t, all respectively, so that thereverse and forward clutches 293 and 289, respectively, stand releasedand the mechanism 2.2i is in neutral position. The valve stem 333 isheld in the neutral position shown by the engage- :ment of a springactuated ball 34u engaging a notch 347 in the land 335.

To start the car or train moving forward, the valve stem 333 is firstmoved to the right until the ball 345 engages a notch 34S. This stemmovement causes the lland 335 to mask the sump port 331 `andtherintermediate land 335 to unmask the inlet port 326 and connect thesame to the outlet port 329, while the outlet port 323 maintainscommunication with the sump port 333. Accordingly, the forward clutch239 is fully engaged and thereafter power input to the converter 272 isestablished :by shifting the regulating valve piston 312. to the left toraise the static pressure in the converter 272 and to start the shell256 moving in the direction to engage the master clutch 263. A steplcsscontrol on .the torque and speed transmitted to the load shaft 232 istherefore obtainable merely by varying the intensity of contact of theplates of the master clutch 253, every such change bein-g accompanied bya change in the static pressure in the converter 272.

To shift from forward to reverse, the master clutch 263 is preferablyreleased andthe valve stem 333 is shifted to the left until the ball34e-engages a notch 349 in the land 335. This stem position causes theland 334 to mask the sump port 330 and the intermediate land 336 to movesufliciently to communicate the inlet and outlet ports 326 and 328,respectively, while the connection of the outlet port 329 to the sumpport 331 is maintained. Thereafter, the master clutch 263 is controlledas stated.

Referring to FlG. 1l, there is shown a further modied power train thatis adapted for electric train service which differs generally from FIG.in that the clutchgear mechanism interposed between the converter andload shaft is conditioned so that both clutches in this mechanism may besimultaneously engaged to `hold the electric train stationary and inwhich either clutch in the stated mechanism is controllably engaged tobrake the load shaft under overhauling load conditions, such as when thetrain is slowing to a stop or it is desired to maintain the train at aconstant speed when descending a grade. In connection with the latteraspect is the utilization of hydrodynamic braking provided by theconverter.

Some of the subassemblies in FIG. 1l are identical with thecorresponding arrangements in FIG. 10 and will be generally referred tosince the similarities are apparent from drawing comparison.

In FIG. 11, the numeral 350 designates the constant speed, inductionmotor which connects with a converter input shaft 351 by means of acontrollable, master, friction plate clutch 352 in the same manner as inFIG. l0, the clutch being engaged by an annular shell 353 slidable on areaction member 354 and respectively defining therewith and with theshaft 351 annular, clutch engaging and balance chambers 355 and 356.Interposed between the shaft 351 and a fixed adjacent part 357 is anoverrunning clutch 358 for the purpose of preventing reverse rotation ofthe converter impeller under braking conditions as hereinafterdescribed.

The input shaft 351 connects with the rotating housing 359 of anhydraulic torque converter 35i), the housing 359 carrying an impeller361 which is related in Athe usual manner to a turbine 352 and a stator353 to define a toroidal circuit 354. The stator 363 is held againstrotation during periods of torque multiplication by an overrunningclutch 365 interposed between the hub of the stator 363 and a fixed part366.

The turbine 362 is drivably `connected to an intermediate shaft 367whose output end connects with a load shaft 368 through a clutchcontrolled, forward and reverse gear mechanism generally indicated bythe numeral 369. The mechanism 369 generally differs from the mechanism231 in FIG. 10 `in that the clutches of the former are individuallycontrolled to provide any degree of intensity of contact `between theplates thereof so that either clutch may be fully engaged to providedrive in the appropriate direction, or both clutches may besimultaneously fully engaged to hold the electric train stationary, oreither clutch may be slipped to any eXtent desired for braking.

Specifically for forward drive, the intermediate shaft 367 carries anannular reaction member 370 on whose periphery is slidable an annularshell 371 having an annular end wall 372 for engaging a friction plateclutch 373 against an abutment ring 374 carried by the shaft 357. Theshell 371 and end wall 372 define with the reaction member 370 and shaft367 an annular engaging chamber 375 for receiving pressure oil. Theplates of the clutch 373 are respectively connected to the intermediateshaft 367 and an annular flange 376 which is coaxial with theintermediate` shaft 367 and is carried by a bevel gear 377 carried bythe load shaft 358.

For reverse drive, the intermediate shaft 357 also carries a secondreaction member 378 axially spaced from the reaction member 370 and onthe periphery of the former member is slidable an annular shell 379having an annular end wall 380 for engaging a friction plate `clutch 331against an abutment ring 382 carried by the intermediate shaft 367. Theshell 379 and end wall 380 define with the reaction member 378 andintermediate shaft 357 an annular engaging chamber 383 for receivingpressure oil. The plates of the clutch 381 are respectively connected tothe intermediate shaft 367 and an annular flange 384 carried by asuitably journaled bevel gear 385, the ange 384 and gear 335 beingcoaxial with the intermediate shaft 367 and the gear 385 meshing with anidler bevel gear 386 which in turn meshes with the bevel gear 377, thegear 386 being held against revolution about the intermediate shaft 357.

If it is desired to provide positive means for releasing the forward andreverse clutches 373 and 331, respectively, springs 373a and 331a may beinterposed between the reaction member 370 and an end wall 372EL forminga part of the shell 371 and between the reaction member 373 and an endwall 33621 forming a part of the shell 379, all respectively. Thereaction member 370 and end wall 372ab and the reaction member 378 andend wall 33h2- define with the intermediate shaft 367 chambers 375e and333a which are vented to the atmosphere by passages 375b and 333b, all`respectively. i i i The clutches 352, 373 and 381 and the converter 360are embodied in an hydraulic circuit whose arrangement and control willnow be described. A pump 337 driven by the motor 35) withdraws oil froma typical sump 338 which serves as a collector for all draining parts ofthe hydarulic circuit as presently described and delivers the oilserially through a heat exchanger 389 and filter 40) `to a chamber 401provided in a regulating valve 442 having a piston 463.` The piston 403is manually operable through a spring 464 and its position in relationto a relief outlet 4115 determines the pressure in the chamber 401 whichconnects with one end of a pipe 4116.

The relief outlet 405 connects successively through a pipe 407 and acollector ring 433 with the toroidal circuit 364 between the stator 353and impeller 361 and the oil is discharged from the toroidal circuit 354between the turbine 362 and stator 363 and through a collector ring 439to one end of a pipe 411), all as described for FIG. l0. The other endof the pipe 410 connects with a chamber 411 in a regulating v alve 412having a piston 413 which is manually operable through a spring 414 `andwhose position in relation to a relief outlet 415 determines thepressure in the chamber 411 which connects with one end of a pipe 416.

The pipe 416 connects successively through a collector ring 417 and apassage 413` in the input shaft 351 with the master clutch engagingchamber 355. Anterior to the collector ring 417, the pipe 416 is tappedby a pipe 413 which includes an orifice 419 and is connected through acollector ring 421i with a passage 421 in the input shaft 351 leading tothe balance chamber 355 from which the oil is continuously dischargedthrough an annular .passage 422 to the sump 383. The relief outlet 415connects successively through a pipe 423, a collector ring 424 and apassage 425 in the input shaft 351 with the inner portions of the platesof the master clutch 352 to` supply cooling oil thereto and eventual`drainage tothe sump 337.

Referring to the pipe 4% which suppliespressure to 'manner'. 'shownmerely provides a pair of conduits for connecting acts as a brake.

the clutches 373 and 331 under control as to the clutch selected and thepressure supplied, the delivery end of the pipe 4116 connects with aninlet port 426 provided in a selector valve 427 which otherwise includesoutlet ports 42S and 429 and sump connecting ports 431B and 431.Reciprocable within the casing 432 of the selector valve 427 is a spooltype, valve stem 43.3 having end lands 434 and 435 and spaced therefroman intermediate land 436. In the shown neutral position of the selectorvalve 427, the land 436 masks discharge from the inlet port 426 andthelands 434 and 435 are positioned to place the outlet ports 42S and 429in communication with the sump ports 430 and 431, respectively.

The selector valve 427 connects through a second selector valve 437 withthe engaging chambers 375 and 333 of the clutches 373 and 381,respectively, in the following The second selector valve 437 in theposition the engaging chambers 375 and 3553 through tie selector valve427 with the sump 33S and in another position, due

to its direct connection with the pipe 466, provides for simultaneousengagement of the clutches 373 and 381 to hold the electric trainstationary. Specifically, the outlet ports 428 and 429 connect throughpipes 433 and 439 with inlet ports 441) and 441, all respectively, inthe second selector valve 437 which otherwise includes outlet ports 442and 443 and a second pair of inlet ports `444-444 which, `for a purposepresently explained, connect through a branched pipe 445 with the pipe4116.

Reciprocable within the casing 446 of the second selector valve 437 is aspool type, valve stem 447 having end lands 448 and 449 and spacedtherefrom an intermediate land 541?. In the shown position of the valvestern 447, the inlet ports 444-444 which communicate directly with thepipe 406 are masked by the lands 449 and 451i and the poistion of theintermediate land 451D in relation to the end lands 448 and 449 is suchas to ycommunicate the inlet and outlet ports and respectively, and theinlet and outlet ports 441 and 443, respectively.

VThe outlet port 442 connects successively through a pipe 451, acollector ring 452 and a passage 453 in the intermediate shaft 367 withthe forward, clutch engaging chamber 375, and the outlet port 443connects successively through a pipe 454, a collector ring 455 and apassage 456 in the intermediate shaft 367 with the reverse, clutchengaging chamber 383.

Provision is also made for cooling either of the clutches 373 and 331under engaging conditions or when either For this purpose, a pump 457driven by the motor 35) and having conventional relief (not shown)withdraws oil from the sump 333 for delivery successively through a heatexchanger 458, a lter 459 and a pipe 46) leading to an inlet chamber 461provided in a selector cooling valve 462 which otherwise includes outletports 463 and 464 and a snmp connecting port 465, Reciprocable withinthe casing 466 of the cooling valve 462 is a spool valve stem 467 havingfor purpose of ow control end lands 463 and 469 and spaced therefrom anintermediate land 47d.

The outlet port 463 connects successively through a pipe 471, acollector ring 472 and a passage 473 in the intermediate shaft 367 withthe inner portions of the plates of the forward clutch 373 While theoutlet port 464 connects successively through a pipe 474, a collectorring 475 and a passage 476 in the intermediate shaft 367 with the innerportions of the plates of the reverse clutch 381. Both of these oilsupplies are for the purpose of cooling the plates of the respectiveclutches under controlled conditions and the cooling oil discharged fromthe clutches 373 and 381 collects in the sump 383.

The Valve stem 467 is maintained in any one of three selected positionsby means of axially spaced notches 477, 478 and 479 provided in a land4319 forming part of the valve stem 467 and which are selectivelyengaged by 16 a spring actuated ball 431. in the position of the valvestem 467 as shown, the ball 481 seats in the center notch 473 to therebycommunicate the inlet chamber 461 with the sump port 465 and to bar nowfrom the inlet chamber 461 to either of the outlet ports 463 and 464.

ln describing the operation of the FlG. 1l power train, it will beassumed that the electric car, bus or train is at rest with the motor356 running at constant speed and all valving controls in the severalpositions shown. All output ot the pump 337, which is driven by themotor 3519, is then succesively through the regulating valve 462,converter 363, regulating valve 412, pipe 423, collector ring 424 andpassage 425 to the plates of the clutch 352 and thence to the sump 338,the clutch 352 being released. Similarly, the output of the pump 457moves through the cooling valve 462 to the sump 38S.

The selector valve 427 is held in any one of three positions by a springactuated ball 432 engaging selected notches 4F33, 484 and 435 providedin the land 434 and in the neutral position shown, the ball 482 engagesthe notch The second selector valve 437 is held in either of twopositions by a spring actuated ball 436 engaging notch 437 or 43S and,in the position shown, the ball 436 engages notch 433. Since theselector valve 427 is in neutral position and the second selector valve437 is in a position denying flow through the pipe 445, the forward andreverse clutches 373 and 331, respectively, stand released.

For a smooth start in forward direction, the selector valve stem 433 ismoved to the right until the ball 432 Yseats in the notch 433 to causethe land 434 to mask the sump port 430, to connect the inlet and outletVports 426 land 423, respectively, to thereby provide a pressure lineconnection from the pipe 456 through the pipes and passages referred toabove including the second selector valve 437 to the forward, clutchengaging chamber 375, and to maintain communication between the outletand sump ports 429 and 431 so that a pressure connection does not existto the reverse, clutch engaging chamber Since the regulating valve 432is in its lowest pressure setting position, the pressure in pipe 436 isvery low 'and is effective to only cause an incipient engagement of theplates of the forward clutch 373.

Coincident with the mov-ement of the selector valve stem 433 to forwarddrive positon, the cooling valve stem 467 is also shifted to the rightuntil the ball 481 seats in the notch 477.' This positioning of thestern 467 causes the lands 463 and 473 to mask the sump and outlet ports465 and 464, respectively, and to connect the inlet chamber 461 with theoutlet port 463, thereby providing a cooling oil flow to the plates ofthe forward clutch 373 which is about to be engaged.

Pressure in the pipe 406 is then gradually increased up to the maximumpressure through the regulating valve 4112 by shifting a plunger 439 andthroughthe spring 434 moving the piston 433 to the left and therebyestablishing maximum torque transmitting condition of the forward clutch373. Final power connection between the motor 35@ and the load shaft 368is achieved by engaging the master clutch 352. This step is accomplishedby the regulating valve 412 and specifically by compressing the spring414 by a plunger 490, thus shitting the piston 413 to the left andgradually applying engaging pressure to the clutch engaging chamber 355and constantly supplying cooling oil to the plates of the master clutch352. As in the other modications, the capacity for slipping the masterclutch 352 under precise control provides for a stepless variation inthe torque and speed transmitted to the load shaft 36S.

For movement in reverse direction from a standing position, theregulating valves 402 and 412 lare in the shown positions and the valvestems 433 and 467 of the selector and cooling valves 427 and 462 areshifted to the left to engage the ball 432 with the notch 485 and theball 481 with the notch 479, all respectively. The second selector valve437 remains in the position shown. With these positionings of theselector and cooling valves 427 and 462, respectively, it will beapparent that a pressure connection is made to the engaging chamber 333of the reverse clutch 331 and cooling oil flow is established to theplates of this clutch. Thereafter, the operations of the regulatingvalves 4112 and 412 are the same as for forward drive with respect topressure control, namely, the valve 4612 first establishes fullengagement of the reverse clutch 3h11 and, thereafter, the valve 412establishes any desired engagement of the master clutch 352.

If it is desired to brake the electric train while moving forwardly, themaster clutch 352 and the forward drive clutch 373 are released bymoving the regulating valves 4112 and 412 to the relieving positionsshown in FIG. 1l and the selector and cooling valves 427 and 462aremoved to the reverse drive positions in which the balls 4&2 and 431engage the notches 465 and 479, all respectively. The regulating valve402 is then controllable to gradually raise the pressure in the pipe 496and hence in the engaging chamber 333 of the reverse clutch 381, theplates of the latter clutch being constantly supplied with cooling oilthrough the cooling oil valve 467. With the reverse clutch 381 engaged,the load shaft 368 through the bevel gears 377, 386 and` 385 causes theturbine 362, to rotate reversely and sincethe stator 363 is held againstrotation by the overrunning clutch 365, the torque is hydrodynamicallyabsorbed in the converter 361i. This torque absorption may be variablycontrolled for obvious reasons by the regulating valve 402. Theoverrunning clutch may be employed to prevent reverse rotation of theimpeller 361 under braking conditions.

The braking action above occurs with the master clutch 3572 fullyreleased, but additional hydrodynamic braking effect can be secured inany variable amount and under the above conditions by operating theregulating valve 412 to establish any desired engaging pressure in themaster clutch chamber 35S. The impeller 361 then rotates inits usualdirection and oppositely to the then reversed rotation of the turbine362..

When the electric train has been brought to a stop, it is heldstationary through the medium of the second selector valve 437, thevalve stem 447 thereof being shifted to the right until the ball 486seats in the notch 487. The lands 443 and 454i then respectively maskthe inlet ports .4413 and 441 hitherto providing connections with theselector valve 427 and the lands 45d and 449 uncover the ports 444-444which connect with the pipe 445. V"ll`he selector valve 427 isaccordingly bypassed and pressure oil, the regulating valve 4412 beingsuitably positioned, is admitted through the second selector valve 437,pipes 451 and 454, and passages 453 and 456 to the engaging chambers 375and 383, all respectively. The forward and reverse clutches 373 and381-, respectively, are therefore simultaneously engaged.

Referring to FIG. l2, there is disclosed a further modification which isbasically identical with the FIG. power train except for the addition ofan hydraulically operated brake which has an actuating member that iscommon with the master clutch. Parts in FIG. 12 which are functionallyidentical with those in FIG. l() are designated by the same numerals.The identical parts and subassemblies are the motor 260, annulus 261,master clutch 263, converter 272 and the oil supply thereto, relief andregulating valves 302 and 311, respectively, selector valve 327` and theclutch-gear mechanism ZSI.

The power connection made by the master clutch Zd is to a converterinput shaft 491 that is drivably conl nected in the conventional mannerto the rotating housing 271 of the converter 272. The input shaft 491carries a reaction member 492 that is held against axial 13 movement andon whose periphery is slidable a cylindrical shell 493 having annularend walls 494 and 495 which define with the shaft 491 and reactionmember 492 annular master clutch and brake engaging chambers 496 and497, respectively. When the shell 493 is moved to the left, it engagesthe master clutch 263 against the abutment ring 264 by means ofinfinitely controllable pressures, and when moved to the right, itengages by similarly controllablepressures a friction. plate brake 498against an abutment ring 499 carried by the input shaft 491, the platesof the brake 498 being respectively carried by and slidable relative tothe input shaft 491 and a fixed part 50).

An overrunning clutch 561 is interposed between the input shaft 491 anda coaxial intermediate shaft 502 which otherwise functions like theintermediate shaft 27S in FIG. l0. The purpose of the clutch 501 `is toprevent the turbine 274 from rotating faster in the normal directionthan the impeller 273 `and to always permit the impeller 273 to rotatefaster than the turbine 274. A further minor difference from FIG. l()resides in the cooling oil supply to the forward and reverse clutches289 and 293, respectively. In FIG. 12, this is accomplished by tappingthe oil supply pipe 304 to the toroidal circuit 280 by a pipe 5413including a throttling orifice 594, the

delivery end of the pipe 593 communicating through a collector ring 505with the passage 3,46 leading to the plates of the clutches 289 and 293,The selector valve 327 is operable to control the forward and reverseclutches 239 and 293, respectively, in the same manner as described forFIG. l0.

Controllable engaging pressure for the master clutch 263 and brake 49Sand cooling oil for the plates thereof, respectively, are determined by`a selector valve 596 interposed between the regulating valve 311 andcooling oil, clutch and brake engaging passages in the input shaft 491.

For the master clutch and brake engaging pressure,` a pipe 5117 connectsthe chamber319 with an inlet port S08 in the casing of the selectorvalve 5% which otherwise includes, in operative relation to the inletport 598, sump connecting ports 511i and 5,11, and outlet ports 512 and513, the casing of the selector valve 506 being designated by thenumeral 509. The port 512 connects successively through a pipe 514, acollector ring S15 and a passage 516 in the input shaft 491 with thebrake engaging chamber 497, and the port 513 connects successivelythrough a pipe 517, a collector ring 518 and a passage 519 in the inputshaft 491 with the master clutch engaging chamber 496.

For the cooling oil to the plates of the master clutch 263 and brake49S, a pipe 529 connects the relief outlet 314 of the regulating valve311 with anzinlet port 521 in the casing 509 which otherwise includes,in operative relation to the port 521, outlet ports 522 and 523. Theport 522 connects successively through a pipe 524, a collector ring 525and a passage 526 in the input shaft 491 with the inner portions of theplates of the master clutch 263 from which the oil drains to the sump299, and the port 523 connects successively through a pipe 527, acollector ring 528 and a passage 529 in the input shaft 491 with theinner portions of the plates ofthe brake 493 from which the oil drainsto the sump 299.

To control the selector valve 506, a valve stem 530 is reciprocable inthe casing 599 in operative relation to the several ports of the valve596 and is provided with suitably spaced lands 53:1, 532, 533 and 534and is held in the position shown, which is that of start, by a springactuated ball 535 engaging a notch 536 in the land 534. In this startposition, the lands 534 and 533 respectively unmask the sump and outletports 51@ and 512 so that pressure does not exist in the brake chamber497, `and the lands 533 and 532 are related, they land 532 additionallymasking the sump port 511, so as to establish a pressure connectionbetween the inlet and outlet ports aeoaois 5d@ and 513 and theconnecting pipe and passages leading to the master clutch engagingchamber 4%.

Por the cooling oil, the lands 532 and 531 are related to connect theinlet and outlet ports 521 and 522, respectively, so that cooling oilcan flow through the indicated pipe and passage to the plates of themaster clutch 263, while the land 531 masks the outlet port 523 so thatcooling oil cannot flow to the plates of the brake 49S. lt will be notedthat while the described position of the -valve stern 53h establishes apressure connection to the master clutch chamber 4%, actually thepressure in the pipe 567 is very low due to the fully retracted positionof the regulating valve piston 312 and the fact that the pipe 525iconnects through the selector valve Sito with the plates of the masterclutch 253 and thence with the sump 299.

Considering the electric train stationary with the motor 260 running atits constant speed, the stated high pressure existing in the pipe 363,and the valve stem 530 in the position shown, the first step ininitiating forward move-ment is, as described for FIG. l0, the shiftingof the selector valve 327 to the position determining full engagement ofthe forward drive clutch 239. Piston Vvalve 312 is then shifted to theleft to any extent desired and, as also described for PEG. 10, tothereby con- `trollably apply pressure through the pipe 507 to themaster clutch 263, the control being smooth, stepless and of infinitevariety. At the same time, cooling oil is continuously supplied throughthe pipe 52) to the plates of the master clutch 263.

To brake, the regulating valve 31E; is returned to the fully retractedposition shown which releases the master clutch 263 and the valve stem53@ is shifted to the right until the ball 535 seats in a notch 537. Theland 534i then masks the sump port Slt?, and the relation between thelands 53?; and. S32 is then such as to communicate the outlet port 13and hence the master clutch chamber 496 with the sump port Sill, and therelation between the lands 533 and 534 is such as to communicate theinlet port SGS with the outlet port SEZ and hence with the brake chamber497. The regulating valve 311 then controllably applies pressure to thebrake 498 in the same mannervthat it did to the master clutch 263. Atthe same time, cooling oil is continuously supplied to the plates of thebrake 498 since the land 532 then masks the outlet port 522 connectingwith the plates of the master clutch 263 and the land 531i then placesin communication the inlet port 521 and the outlet port 523 leading tothe plates of the brake 493. With the master clutch 263 released, somebenefit will be secured from hydrodynamic braking in the converter 272due to bach drive therethrough.

In FIG. 13 is shown a further modification of FlG. l0 which is identicaltherewith as to basic components and differs therefrom in the use of anhydraulically controlled retarder for braking and the selective shift ofoil flow to the converter or the retarder depending upon whether powerflow or braking is desired. Parts in FIG. 13 which are functionallysimilar to those in FIG. 1G are identilied by the same numerals.

In FIG. 10, the relief outlet of the relief valve connects with thetoroidal circuit 2S@ of the converter 272 by the pipe Edit, but in FIG.13, the indicated outlet of the relief valve Sil?. connects by a pipe5.53 with an inlet port 53@ provided in the casing 54d of a selectorvalve 541 which otherwise includes a sump connecting port 542 and outletports 543 and 544. The outlet port 543 connects successively through apipe 545 and a collector ring 54,6 with the toroidal circuit 23@ in thesame manner as described for FIG. 10 and the discharge from theconverter 272 is successively through a collector ring 547 and a pipe543 to the chamber 3MB* of the regulating valve Sill whose relation toand control of the master clutch 263 is the same as in FG. 10.

The outlet port 54d connects by a pipe 549 with the stationary bladedmember of an annular, hydraulic retarder 551 whose bladed rotatingmember 552 is fast to the intermediate shaft 275 yand which cooperateswith the stationary member 5S@ and defines therewith an annular workingchamber S53 which, by way of example, is shown as having a circularcross section. ln effect, the retarder 55'?. resembles an hydrauliccoupling under a stall condition.

The working chamber 553 connects by a pipe 554i with a chamber 5.35provided in the casing 556 of a controllable regulating valve 5:37 whichotherwise has a relief port S58 connecting with the sump 299. Flow fromthe chamber S55 to the relief port S55 is controlled by a piston 559reciprocable in the casing 556 and actuated towards the left through aspring 56d.

Considering the FlG. 13 power train with the motor 26d running atconstant speed and the parts in the positions shown, the relief valve362 has established the relatively high pressure in the pipe 3dS. Forthe selector valve 541 which includes a valve stem 561 of the spool typereciprocable in the casing 54d and having spaced lands 562, 563 and 564,the stem 561, in the position shown, is held by a spring actuated ball56S engaging a notch 566 in the land S64. In the position shown, therelation of the lands 553 and Soft is such that the inlet and outletports 539 and 543, respectively, `are in cornmunication and relief oilfrom the relief valve 302 may iow to the converter toroidal circuit 28%.Further, the relation of the lands 563 and 562 is such that the sump andoutlet ports 42 and 545;, respectively, are in cornmunication and theworking chamber 553 of the retarder 551 accordingly connects with thesump 299. The regulating valve 557 is in the full open position shown.

The electric train is started in` a forward direction in the same manneras in FlG. 10, i.e., the forward clutch 2o9 is first fully engagedfollowed by the controlled engagement of the master clutch 263, theconverter 272 being supplied `and filled with working oil throughselector valve 541 in the shown position. To retard movement of theelectric train, the master clutch 263 is re` leased as described aboveand the selector valve 'stem Sol is shifted to the right until the ball65 engages the notch 567. The land 564 then masks the outlet port 43 andthe position of the land 563 is such that the inlet `and outlet ports539 and 544, respectively, are placed in communication so that oil issupplied to the working chamber S53 of the retarder 551 and thetheretofore communication of the latter with the sump port 5ft-tl ismasked by the shifted position of the land 563. Braking action by theretarder 551 is controlled in the obvious manner by controlling thepressure therein by the regulating valve 557.

Since the braking effectiveness of the retarder .555i is higher atrelatively high than at relatively low spe-eds, it is recognized thatconventional equipment may be used to brake at low speeds and to holdthe electric train stationary.

ln FlG. 14 is fragmentarily shown a modification which may beincorporated in the FIGS. 10 to 13 arrangements but which isspecifically shown as applied to the FIG. 12 transmission and whichemploys a variable clutch controlled gear mechanism which enables theconverter impeller to be rotated at a higher speed than that of theconstant speed power source to obtain greater acceleration duringselected periods of operation. Where parts and subassernblies in FlG. 14are identical with those in PEG. l2, they are identified by the samenumerals.

The constant speed power source Zdtl is drivably connected to an annularshell fied which in turn is connectible through a first master, frictionplate clutch Se@ to one end of a converter input shaft 579 whoseopposite end connects with the rotating housing 271 of the converter272. Carried by the shaft 57@ and held against axial movement is anannular reaction member 571 on

12. A POWER TRANSMISSION COMPRISING IN SERIES POWER FLOW RELATION, FIRSTAND SECOND, MASTER CLUTCHES OF THE FRICTION PLATE TYPE AND ARRANGED FORSELECTIVE CONNECTION TO AN ELECTRIC INDUCTION MOTOR AND AN HYDRAULIDTORQUE CONVERTER HAVING A TOROIDAL CIRCUIT, EACH MASTER CLUTCH INCLUDINGA CHAMBER FOR RECEIVING PRESSURE OIL TO ENGAGE THE ASSOCIATED CLUTCH,THE FIRST MASTER CLUTCH BEING DIRECTLY CONNECTED TO THE MOTOR, A GEARTRAIN CONNECTING THE SECOND MASTER CLUTCH TO THE MOTOR AND ARRANGED TOPROVIDE FOR A HIGHER ROTATIVE SPEED OF THE SECOND CLUTCH WHEN ENGAGEDRELATIVE TO THAT OF THE FIRST CLUTCH WHEN ENGAGED, AND AN HYDRAULICSYSTEM INCLUDING AN OIL SUPPLYING PUMP, THE TOROIDAL CIRCUIT, AREGULATING VALVE HAVING PRESSURE CONNECTIONS WITH THE FIRST AND SECONDCLUTCH CHAMBERS AND RELIEF OUTLET CONNECTIONS WITH THE PLATES OF THEFIRST AND SECOND CLUTCHES, BOTH OF SAID LAST NAMED CONNECTIONS INCLUDINGA SELECTOR VALVE SHIFTABLE BETWEEN ONE POSITION DETERMINING ANENGAGEMENT OF THE FIRST CLUTCH, A SUPPLY OF COOLING OIL TO THE PLATESTHEREOF AND RELEASE OF THE SECOND CLUTCH AND ANOTHER POSITIONDETERMINING AN ENGAGEMENT OF THE SECOND CLUTCH, A SUPPLY OF COOLING OILTO THE PLATES THEREOF AND RELEASE OF THE FIRST CLUTCH, AND MEANS FORINFINITELY CONTROLLING THE REGULATING VALVE TO VARY THE PRESSURE IN THECHABER OF THE CLUTCH BEING ENGAGED.